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what's the difference between these and the Trolltech versions of Qt?
Can I use these builds to get Linux Qt projects compiled and executed under Win?
Or is it kind of beta software?
Are these versions GPL licensed?

This is based on Qt/X11. The goal, AFAIK, is to provide an implementation fully compatible with the Qt/Win32 commercial version, only GPL. Right now I think would be considered still in beta state, but I'm not sure.

What do you read at which point in the roadmap they are? The frontpage says "We are looking for developers to finish milestone 4 of the Roadmap" and milestone 4 in the roadmap is "Stage 7 - start native kde port".

Lots of beta software works well, but still isn't anywhere near done. I wrote a QT app a while back and tried compiling it for Windows. Turns out QScrollviews were broken at the time. There's probably other stuff in there that is broken as well, and in something like Qt you can't really call it done until everything works.

Not to knock the authors, I was shocked and amazed to see my app compile and run with no effort at all. It's an amazing accomplishment in itself to make as much progress as they have made.

They're all GPL. It's pretty much like anything under cygwin, most things work but it underperforms some of the time and it isn't so reliable. So I'd say beta, yes. The cygwin one is just the ordinary qt recompiled for cygwin, wheras the native port is a port of Qt back to windows so we have a gpled windows version, and IIRC is a bit kludgy and missing things. (but performance will be perfectly native).

Trolltech is going to release a GPLed version of QT for Windows for QT4. Also it is still licensed under the GPL so it works exactly the same as every other desktop (GPLed software can use the GPL version, everything else and you need a QT license).

Trolltech makes money selling /all/ the versions, they just also give it away under the GPL on all platforms (had been all but windows, then they stopped for a while, and with QT4 they are going to do it for all platforms the same again).

Q: Why do I need to buy a commercial edition when I can get it for free?

A: If you want to develop Open Source Software, you are welcome to use our Qt Open Source Edition. If you don't want to develop Open Source Software (for example to keep your source code secret or to produce commercial software), you must purchase a commercial edition of Qt.

Their FAQ is actually wrong on that point, and bad on a few others. If I keep my modification to myself (private or "secret") the GPL does *NOT* require me to release that source under the GPL. I only have to do that if I distribute or "release" it. See:

[[ http://www.gnu.org/licenses/gpl-faq.html#GPLRequireSourcePostedPublic
The GPL does not require you to release your modified version. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and use it internally without ever releasing it outside the organization.
]]

Normally if you develop something you will later distribute it, just because the developer is normally not the user.
I would say in >99% of the development of closed source software this is the case on for these the FAQ is correct.

So what is the exact definition of a developer, developing software where he/she doesn't want to distribute the software to anybody and still keep the code secret?

Huh, developer/user distinction? You're developing software so that someone can *use* it. Once you give that someone the software, you *have* to provide them with the source if the GPL is enforced. And as soon as the user gets the software he can distribute it beyond your control. It doesn't matter of the user is internal or not. That user gets GPL software and can use it as GPL software.

So your company has no control over what its internal users do with the software. They can distribute it to the outside world because it's GPL. They can use the code in other GPL products of their own.

They do make a distinction between *using* it inside an organisation and *distributing* it to the public.

Giving modified software to an employee of your own organisation does *not* count as distribution. He does not receive the changes under the terms of the GPL and thus *cannot* redistribute it legally to someone outside the organisation.

Note: Modified source in the GPL FAQ means what is called a derived work in other places, so what is said in the FAQ applies to software written with the GPLed Qt.

Then anyone you distribute the program to within your organization gains the GPL rights to distribute the program and source. A company who wants to keep their code secret and conform to the GPL clearly can't do it.

I'm not sure what part of the English text in the GPL and their FAQ you don't understand, but simply stating something about something that is contrary to the explicit text doesn't do it for me. A person acting as an agent on behalf of a company is different than an ordinary individual. In any case, even if I had to give a proprietary tweak I made on behalf of my company to another employee within that company, we can both be bound by contract to that company not release it publicly.

>we can both be bound by contract to that company not release it publicly.
Actually no, the GPL explicit disallows placing additional restrictions upon the GPL'ed material. Trying to apply a contract like that to GPL'ed material would break the GPL.

> A: If you want to develop Open Source Software, you are
> welcome to use our Qt Open Source Edition. If you don't
> want to develop Open Source Software (for example to keep
> your source code secret or to produce commercial
> software), you must purchase a commercial edition of Qt.

This answer also seems wrong since your not allowed to use a GPL incompatible license that is "open source". I think this can be boiled down to the old "open source" vs "free software" naming issue.

I think if Stallman had forseen all these naming issues around "free software", he'd've chosen another name.

> This answer also seems wrong since your not allowed to use
> a GPL incompatible license that is "open source".

Incorrect. Qt is released under GPL, QPL and commercial licenses. You use GPL for GPL programs, you use QPL for all other Open Source programs (like BSD, Apache, whatever), and commercial for closed source.

Qt (and MySQL for that matter) should stop using the term commercial software for proprietary software. You can very well use free software commercially. Two examples:
1. Linux distributions: I use Suse that I bought from the store.
2. Siteseed is a free software web development platform that is used by a Portuguese company to deploy websites for their clients with the source completely free.

> when trolltech releases qt for windows in gpl that will make the project what this topic is about redundant and useless.

Trolltech will only release Qt 4 under GPL but no Qt 3.3. All Qt 3 based stuff would have to be ported to Qt 4 without this project before being possible available under Win32, and if KDE 3 based it will take well over a year to have KDE 4 ported/released before you can start. So working on Qt3/WFE and KDE3 based ports makes sense short-term.